Causes Of Endometriosis

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Causes Of Endometriosis

Endometriosis is one of the most common gynecological disorders in the world. It occurs when the tissue that is normally supposed to form the lining of the uterus starts to grow elsewhere in the pelvic cavity, causing painful lesions that can also lead to infertility. Although doctors don’t know for sure what causes endometriosis, common theories include genetic factors, hormonal factors, retrograde menstruation, immune system disorders, and surgical incidents.

Endometriosis is one of the most common, yet not completely understood, gynecological disorders in the world. Any woman who has started her period can develop endometriosis, but it is particularly common among women in their 30s and 40s. Experts conservatively estimate that about 3–10 percent of all women of reproductive age suffer from endometriosis worldwide. In the US alone, that translates to more than 5 million women!1 That said, studies have shown that about 11 percent of women who have endometriosis don’t present any telltale symptoms, so the actual number of women who have this condition could be considerably higher.

What Is Endometriosis?

The American Congress of Obstetricians and Gynecologists (ACOG) defines endometriosis as a condition where the tissue that is normally supposed to form the lining of the uterus (that is, the endometrium) starts to grow elsewhere in the pelvic cavity, such as the Fallopian tubes, ovaries, outside the uterus, or the outer surfaces of the bladder, ureters, bowel, and rectum. It may even grow in the cul-de-sac, which is the space between the rectum and the uterus. In very rare cases, the tissue grows outside the pelvic cavity – on the lungs, brain, spinal cord, knee, nose, and other body parts too!2

Patches of endometriosis are often referred to as lesions, implants, or nodules. Implants can vary by size, color, and shape but in the early stages, they are usually very small and have the appearance of clear pimples. However, as they grow, they may develop into small nodules, flat injured areas called lesions, or cysts called endometriomas. Cysts can be smaller than a pea or larger than a grapefruit. They could be variously colored too – red, colorless, or very dark brown. Cysts usually form on the ovaries and could be filled with old, thick, dark brown blood.3

Causes Of Endometriosis

Despite being a highly active area of medical research, no one knows for sure (yet) what causes endometriosis! Several plausible theories have been put forth, so let’s take a look at some of the most accepted ones.

1. Hormonal Factors

It is clear that estrogen is the hormone that contributes to endometriosis. A long exposure to estrogen can result in endometriosis, as in cases of obesity, short menstrual cycles, and early-age menstruation. Receptors in endometrial cells bind to estrogen and another important hormone progesterone, both of which promote growth and thickening of the uterus. And when these cells attach to body parts and organs outside the uterus, and hormonal functions continue, it results in scarring and bleeding.4 5

2. Retrograde Menstruation

One of the most widely accepted theories on why endometriosis occurs is that some of the uterine tissue that is shed during your period flows back into the pelvic area or abdominal cavity through the Fallopian tubes instead of flowing out through the vagina. This phenomenon is commonly referred to as “retrograde menstruation.” However, retrograde menstruation does not fully explain endometriosis because nearly all women experience some level of retrograde menstruation but only a few get endometriosis.6

3. Immune System Issues

Disorders in the overall immune system may contribute to endometriosis.

  • The immune system may not be able to detect and destroy endometrial tissue the way it should, and that allows the tissues to grow outside the uterus. This may explain why women with endometriosis also tend to suffer from autoimmune diseases such as Sjögren’s syndrome, rheumatoid arthritis, and inflammatory bowel diseases like Crohn’s disease and ulcerative colitis.7 8 The connection, however, is still not clear and researchers are yet to decide if endometriosis should be treated as an autoimmune condition.
  • On the other hand, the pain, infertility, and damage caused by endometriosis could be due to an overactive immune system. The body may perceive the endometrial implants to be hostile and attack them. Macrophages or large white blood cells are always high in women with endometriosis. Macrophages produce very powerful factors such as cytokines and prostaglandins, both of which cause inflammation and damage in cells and tissues.9

4. Genetic Reasons

There is a very strong possibility that endometriosis is genetically inherited since a family history of endometriosis makes you much more likely to have it.10 Studies are still exploring exactly how endometriosis may be passed on from mothers to daughters. Some researchers also believe that endometriosis is a birth abnormality where endometrial cells develop outside the uterus in a female fetus. Later in life, when this female child starts her period, these cells become painful lesions.11

5. Surgery

Surgical procedures can sometimes cause endometriosis. For instance, if a woman has had endometriosis undergoes surgery in the abdominal or pelvic area (including a C-section), she could have some endometriosis implants attach to the surgical incision. That could lead to endometriosis in the surgery scar later in life.12

6. Transformation Of Cells

Researchers believe that sometimes cells outside the uterus change and become like the cells that line the uterus. That is how endometriosis occurs in unexpected sites such as the thumb or the knee.13 But why this happens is yet beyond medical science’s undertsanding.

7. Movement Of Cells

Another reason attributed to endometriosis in other body organs such as the lungs is that the cells from the uterine lining travel through the lymphatic system or blood vessels and attach to these parts.14

8. Unexplained Causes

Endometriosis has been known to develop in women after hysterectomy too and, so far, no satisfactory explanation has been found for that. Another unexplained situation is the rare occurrence of endometriosis in men who have been exposed to estrogen during medical treatments.15

Why Does Endometriosis Hurt So Bad?

Endometriosis implants are highly responsive to changes in your estrogen levels. As a result, they grow, thicken, break down, and bleed just like the lining of your uterus bleeds each month when you get your period. When the endometriosis implants/lesions start to bleed, the blood has nowhere to go. Instead, the implants become deposits of blood that form patches, spots, and cysts. In such situations, the surrounding area can easily become inflamed and irritated. When this happens every month, it can produce scar tissue that can be extremely painful, especially just before and during your menstrual cycle.16

Sometimes, endometriosis implants can even cause your pelvic organs to adhere to each other. These web-like adhesions can cause scar tissue, which in turn results in pelvic pain. Endometriosis nodules can also press up against nerves cells that are in close proximity to your pelvic area, which is – you guessed it – also painful.17

Pain associated with endometriosis can be debilitating to the extent that it can interfere with everyday activities and diminish one’s quality of life. Endometriosis pain is usually chronic, lasting 6 months or more.18 For some women, endometriosis pain decreases once they reach menopause because that’s when the body stops producing estrogen.19

Endometriosis Signs And Symptoms

It is important to restate that many women show absolutely no symptoms of endometriosis. However, some of the most common symptoms and signs associated with endometriosis include:

  • Heavy periods
  • Irregular periods
  • Bleeding or spotting in between periods
  • Debilitating menstrual cramps that don’t go away with OTC painkillers
  • Difficulty conceiving or infertility
  • Abdominal pain and/or pain in the pelvic region or lower back before and during a period
  • Constant pelvic pain20

Painful sex, bowel movements, or urination can also be symptoms of endometriosis.21 Many women diagnosed with endometriosis may also experience fatigue, exhaustion, low energy levels, painful bladder syndrome, back pain, or gastrointestinal issues such as constipation or diarrhea. Depression is a possible effect of endometriosis too.22

For a vast number of women, difficulty getting pregnant and/or infertility is usually the first telltale sign of endometriosis. A whopping 33 percent of all female infertility cases can be attributed to endometriosis.23 While endometriosis does not make it impossible to have kids, it does make it more difficult to conceive due to the location of endometriosis implants. If endometriosis lesions occur in the Fallopian tubes, it interferes with the passage of the egg; if they occur in the ovaries, it blocks the release of the egg.24

Research suggests that there is a significant relationship between endometriosis and the following health conditions:

  • Chronic fatigue syndrome
  • Fibromyalgia
  • Autoimmune diseases such as lupus, rheumatoid arthritis, and multiple sclerosis. The body’s immune system attacks itself instead of the illness.
  • Asthma
  • Allergies
  • Ovarian and breast cancer25

Endometriosis Risk Factors

As we have mentioned before, any woman who menstruates can develop endometriosis. You are, however, more likely to have this condition if:

  • Your mom or sister has endometriosis. A family history of endometriosis makes you six times more likely to have it too.
  • You started your period before the age of 11.
  • Your menstrual cycle is shorter than 27 days.
  • Your period is particularly heavy and lasts more than a week.26

Endometriosis Protective Factors

Just like there are factors that increase your chances of having endometriosis, other variables can lower the chances of developing this condition. Endometriosis protective factors include:

  • Having a low body fat percentage
  • Exercising more than 4 hours per week
  • Pregnancy
  • Starting your period later on in adolescence. This factor is, of course, beyond anyone’s control.27

In addition, consuming plenty of fruits, leafy greens, and foods rich in omega 3 fatty acids can also protect against endometriosis.28

Dispelling An Important Endometriosis Myth

Endometriosis is a highly active area of research in the medical community today and ongoing investigations are helping researchers better understand this condition. Newer scientific evidence has disproved some long-held beliefs about endometriosis.

Previously, medical experts believed that the intensity of endometriosis pain depended on the size and location of the endometriosis patches/implants. Recent studies have disproved this theory and we know now that the size or location of the implants/nodules has nothing to do with the severity of the pain.29 In fact, some women with small lesions experience intense pain while others with large lesions experience very little pain.30

Can I Prevent Endometriosis?

Not really. There’s no sure-fire way of preventing endometriosis, but you can try to reduce your chances of developing it by lowering the amount of estrogen in your body. This is after all the hormone responsible for thickening your uterine lining each month. Some ways you can lower estrogen levels include:

  • Hormone-based birth control methods. Discuss birth control pills or patches that have lower estrogen levels with your OB/GYN.
  • Avoid excess alcohol. Limit intake to about 1 drink per day.
  • Avoid excess caffeine. Too much coffee, sodas, or even green tea can raise your estrogen levels. Stick to about one caffeine beverage a day.
  • Exercise regularly. Getting at least 4 hours of exercise a week will regulate your estrogen levels.31

References   [ + ]

1. How many people are affected by or at risk for endometriosis? National Institutes of Health.
2, 16, 21. Endometriosis. The American Congress of Obstetricians and Gynecologists.
3, 5, 9, 18, 23, 24. Endometriosis. University of Maryland Medical Center.
4, 7, 26, 27, 29, 30. Endometriosis: Condition Information. National Institutes of Health.
6, 12, 13, 14. Endometriosis. UCLA Health.
8. Endometriosis and co-morbidities. Endometriosis.org.
10, 19, 25, 31. Endometriosis. Office on Women’s Health.
11. Endometriosis. American Pregnancy Association.
15. Causes of endometriosis. Endometriosis UK.
17, 22. What are the symptoms of endometriosis? National Institutes of Health.
20. Endometriosis. U.S. National Library of Medicine.
28. Endometriosis. University of Maryland Medical Center.